The development of the high-resolution cell-specific map of the neural activity associated with a particular behavior presents one of the major challenges in modern neuroscience. This dynamic electrophysiological mapping is particularly difficult in behaviors with a strong temporal variability, such as learning or memory. It is furthr aggravated by the limited long-term stability of the existing high-density electrophysiological platforms and the inability to uniquely identify cell types during recording. This project strivesto develop novel multi-functional fiber-inspired neural probes (FINPs) for long- term simultaneous neural recording and optogenetic and pharmacological cell-type identification. Specifically, we will combine soft polymer-based materials with a fiber-inspired fabrication process to create a platform that seamlessly integrates hundreds of micrometer-size electrodes, waveguides and drug delivery channels, while minimizing the potential tissue response to chronic implantation. We will characterize our structures with respect to their tissue compatibility and long-term functionality in chronic experiments in collaboration with Dr. William Shain in Seattle Children's Research Institute (SCRI), who will share his knowledge of histological methods and image analysis. Furthermore, the utility of the proposed FINPs will be evaluated in a basic neuroscience study relevant to learning. FINPs will be used to measure the changes in activity (mPFC) neurons that project to the basolateral amygdala (BLA) as a previously learned fear response is extinguished. The combined behavioral and electrophysiological experiments will be performed in close collaboration with Dr. Alla Karpova at the Janelia Farm Research Campus (JFRC), who will contribute her expertise in mPFC physiology and cell identification techniques.